The board we are using is called “WeMos D1 Mini” and has an ESP8266 module
on it, which we will be programming. It comes with the latest version of
MicroPython already setup on it, together with all the drivers we are going
to use.

Note

The D0, D1, D2, … numbers printed on the board are different from what
Micropython uses – because originally those boards were made for a
different software. Make sure to refer to the image below to determine
which pins are which.

It has a micro-USB socket for connecting to the computer. On the side is
a button for reseting the board. Along the sides of the board are two rows
of pins, to which we will be connecting cables.

The symbols meaning is as follows:

3v3 - this is a fancy way to write 3.3V, which is the voltage that the
board runs on internally. You can think about this pin like the plus side
of a battery.

gnd, G - this is the ground. Think about it like the minus side of
the battery.

gpioXX - “gpio” stands for “general purpose input output”. Those are
the pins we will be using for sending and receiving signals to and from
various devices that we will connect to them. They can act as output –
pretty much like a switch that you can connect to plus or to minus with
your program. Or they can act as input, telling your program whether they
are connected to plus or minus.

a0 - this is the analog pin. It can measure the voltage that is applied
to it, but it can only handle up to 3.3V.

5V - this pin is connected with the 5V from your computer. You can
also use it to power your board with a battery when it’s not connected to
the computer. The voltage applied here will be internally converted to the
3.3V that the board needs.

rst - this is a reset button (and a corresponding pin, to which you can
connect external button).

Many of the gpio pins have an additional function, we will cover them separately.

The board you got should already have MicroPython with all the needed libraries
flashed on it. In order to access its console, you will need to connect it to
your computer with the micro-USB cable, and access the serial interface that
appears with a terminal program.

For the serial interface to appear in your system, you will need to install the
drivers for CH340. Once you have that, you can use either Hyper Terminal,
PuTTy or CoolTerm to connect to it, following this guide.